1. Technical Field
The present invention relates to a snow guard apparatus and method for providing protection from snow and ice falling from a roof. In one aspect, the present invention relates to a snow guard apparatus and method for installation and attachment of a snow guard to a standing seam metal roof.
2. Background
Metal roofs are found on many types of commercial buildings. Metal roofs typically are placed over a plywood or particle board substructure. A metal roof comprises a plurality of metal roofing panels. Each panel has a longitudinal length to cover a span of a roof section, and the panels are laid side by side to cover the width of the roof section. Each panel preferably includes substantially perpendicular edges running along both the left and right sides, and the roofing panels are located such that their substantially perpendicular edges are abutting, thereby forming a seam. The substantially perpendicular edges of abutting panels are each crimped together or bent downwardly over each other to form a joint. The joint seals the adjoining panels, thereby preventing fluid communication breaching to the roofing substructure below the roofing panels, as well as to the area between each roofing panel. Fluid communication to the substructure leads to the substructure becoming rotted, infested, or otherwise losing or degrading structural integrity. Metal roof installers have devised unique patterns for the joints to prevent the breaching of moisture from the exterior surface of the roofing panels to the interior surface via the roofing panel abutment point.
A snow guard is secured to a metal roof to prevent snow from falling off the metal roof, thereby potentially damaging persons and property located in the fall path. A snow guard is attached either to a roofing panel of the metal roof or to the seam of the abutting roofing panels. One attachment method is by screws or bolts. However, both screws and bolts can puncture the roofing panel or seam where they are driven, thereby destroying the hermeticity of the metal roof. While the snow guard is in place, fluid communication preferably is prevented through the holes created by the screws or bolts. Another possible attachment method is by a set screw. Specifically, the snow guard attaches to a groove, a threaded hole from one side of the snow guard to the groove, and an indented portion located in the groove opposite the threaded hole. The set screw typically has a blunt end.
The snow guard is placed over the seam of the metal roof, and the set screw is threaded through the hole. As the set screw is driven into the threaded hole, the blunt end of the set screw contacts a portion of the seam. Further driving the set screw into the hole causes a portion of the seam in contact with the blunt end of the set screw to be driven toward and into the indented portion located in the groove opposite the set screw hole. Bending the seam secures the useful device onto the seam. The set screw tends to tear the seam at the point where the blunt end of the set screw contacts the seam. Specifically, as the blunt end of the set screw is driven further into the hole and contacts the seam, friction is created between the blunt end of the turning set screw and the seam in forced contact therewith. The friction causes the rotational torque imparted to the blunt end as a result of driving the set screw further into the hole to be transferred to the seam. The transferred rotational torque and friction fatigues the seam, causing it to be turned in the same direction as the set screw, thereby producing tears in the seam at the set screw/seam interface. The tears in the seam degrade the hermeticity of the metal roof, leading to possible fluid communication and deleterious consequences.
Snow guards hold snowloads on seamed metal roofs. Snow guards include plates with vertical splines mounted to roofs with mounting blocks, affixed to the splines, fencing flags affixed on top the blocks, and fencing held by the flags. Such snow guard systems permit leakage of moisture down into the buildings covered by the roofs. Sheet metal panels in building construction building attachments interconnect with a metal panel surface. In northern climates, a snow retention snow guard on a metal roof is needed which controls, inhibits, and impedes the movement of snow or ice or combination of snow and icedown the pitch of the roof.
Sliding snow or ice or a combination of snow and ice from roofs can be hazardous to people, the surrounding landscape, property, and building components. Snow or ice sliding from a roof above an entryway may injure passers-by. Similarly, falling snow or ice damages landscape features, such as shrubs and property or building components, including automobiles or lower roofing portions. Sliding snow or ice can shear off antennas, gutters, or other components attached to a building roof or wall, thereby potentially causing a leak.
The problem of sliding snow or ice is particularly experienced in connection with metal roofs, including raised seam roofs, e.g., standing seam roofs, where there is relatively little friction between the roof and the snow or ice. As used herein, the term xe2x80x9craised seam roofxe2x80x9d includes a roof formed by a series of panels interconnected to define longitudinal, raised portions. A snow guard controls movement of snow or ice or a combination of snow and ice across or along selected areas of such metal roofs.
Snow guard devices were developed initially for use on tile and shingle roofs. In one type of configuration for use on such roofs, an L-shaped brace has one leg fastened to the roof and another leg which projects upwardly from the roof. The fastening leg is nailed or screwed into the roof beneath a shingle or tile. By positioning and attaching a plurality of these braces to the roof in substantially linear fashion, linear bars are positioned within and through one or more receiving areas of the respective upwardly projecting legs to provide a fence-like configuration for snow or ice or a combination of snow and ice retention. A plurality of braces for receiving the linear bars are positioned on opposite sides of the roof and are interconnected by a harness assembly. By positioning the brace bar assemblies on both sides of the roof, the snow retention snow guard is held in position.
Other snow retention devices for shingle or tile roofs have utilized a more unitary structure.
Another snow retention device is a snow guard plastic barrier having a generally L-shaped cross-section. The snow guard is installed by smearing the underside of the snow guard with silicon intended to provide a weather seal, positioning the snow guard against the roof surface, and attaching the snow guard to the roof with screws such that the screws penetrate the roofing surface and become anchored into an underlying structural member. An adhesive may be used in place of the screws where desired.
A snow guard device for use on trapezoidal-type, standing seam roofs having 24 inch wide panels comprises a horizontal steel member which spans one panel width. The horizontal member is attached at ends to mounting members which straddle the trapezoidal panel ribs. The mounting members are fastened to the panel ribs by screws.
Snow guard devices may cause the roof to leak. Many of the snow guards are attached to the roof by a screw, nail or other fastener which pierces the roofing surface. Such piercing of the roof leads to undesired leakage because of inadequate sealing or shearing of the fastener by the forces exerted by sliding snow or ice or a combination of snow and ice. In an attempt to prevent leakage, sealants or gaskets or a combination of sealants and gaskets are applied around the holes pierced through the roofing surface. However, these measures complicate installation and may not fully prevent leaks. Alternative methods for the attachment of snow guard devices to roofs such as adhesive bonding may fail to provide secure attachment or may be difficult to install on a sloped surface, particularly where the snow guard is applied to a smooth, non-porous roofing material such as metal.
Snow guard devices can cause undesired pinning of the roofing materials. Metal roofing sheets are designed to be moveable to accommodate normal thermal expansions and contractions. Where snow guard devices are attached to the roof by a screw or nail which pierces the roofing surface and is anchored into an underlying structural member or deck, the designed thermal movement characteristics of the roof are compromised, thereby adversely affecting the roof""s performance.
Snow guard devices are not readily adaptable for use in a broad range of raised seam roofing applications. Some of the snow guards are not intended for raised seam roofing applications at all but, rather, are primarily for use on shingled or other non-raised seam roofs. Other snow guards are designed for use on raised seam roofs having a particular panel width and seam profile and cannot be easily adjusted for use in connection with panels of differing widths or seams of various profiles. Moreover, some snow guard devices are connected permanently to a roof such that the snow guard cannot be easily repositioned as may be desired.
Snow guard devices comprise a snow blocking element having a height, relative to the roof surface, which is unadjustable, difficult to adjust, or adjustable only between a small range of predetermined positions. Accordingly, the user""s ability to adjust such snow guard devices, for particular conditions with respect to snowfall or drifting is limited.
Snow guard apparatus are intended to prevent sheets of snow from sliding off roofs where snow has accumulated. In climates experiencing snow and prolonged cold weather, snow accumulating on roofs becomes a potential safety hazard. After snow has fallen onto a roof, it may remain in place during cold temperatures for an indeterminate period of time. Eventually, as the snow melts, large sheets of snow break off from the accumulated snow. If the roof on which the snow has accumulated is sloped, such sheets suddenly fall off the roof onto unsuspecting individuals or property. The weight of snow sheets frequently is so significant as to cause injury to individuals and serious damage to property.
The potential hazard caused by accumulated snow is particularly dangerous when snow is found on a sheet metal roof. These roofs provide a slippery surface which facilitates sliding of sheets of snow.
A variety of snow guards for preventing snow from falling from particular types of roofs are found in the prior art. West German Patent 2126082, West German Patent 2523087, Austrian Patent 222329, and Switzerland patent 204783 each disclose a type of snow blocking snow guard involving an elongated member held above the roof. The elongated member is held in place by two parallel plates secured to each other positioned on either side of a roof seam. Particular roof designs in which the roof seams snugly fit in between two parallel plates are not easily adapted to fit roof seams of a size or configuration different from the one for which each is designed.
U.S. Pat. No. 2,201,320 issued to Place teaches the use of multiple sheet metal strips with bent ends to hook over roof seams. Such snow guards are manufactured to fit the exact distance between adjacent roof seams.
Brackets attached to roof seams to support elongated supports used as scaffolds are described in U.S. Pat. No. 1,054,091 issued to Darnall. The Darnall mechanism prevents masses of snow from falling from a roof. Each bracket includes a cam lever which engages a roof seam to attach the bracket to the seam.
Three West German Patents 2845104, 2845103, and 3716491 disclose mechanisms used to trap snow on a roof and rely on a plurality of snow retainers, each independently attached to a roof seam. In some cases, the retainer appears to be attached to the seam by means of a screw which penetrates the seam, thus possibly lessening the structural integrity of the seam and inviting leaks in the roof. A snow guard in U.S. Pat. No. 507,776 issued to Berger et al. has teeth or projections which pierce the roof seam with possible detrimental results.
While prior snow guard mechanisms are useful for an intended purpose, no mechanism is available which is aesthetically attractive when installed to prevent masses of snow from falling from a metal roof with standing seams. There is a need for a mounting snow guard positioned on a metal panel surface without adversely affecting roof performance. There exists a need for a snow guard and method which provide an aesthetic appearance and which provide a snow guard secured onto metal roofs of a variety of shapes and sizes, which will decrease the hazard created by sliding snow masses.
It is an object of the present invention to provide an on-the-roof ice and snow-holding apparatus that is easily installed, not requiring special skills for its installation and which is easily relocatable.
It is another object of the present invention to provide an on-the-roof ice and snow holding apparatus that will not puncture or brake, or tear up the seams it is installed upon.
It is yet another object of the present invention to provide an on-the-roof ice and snow holding apparatus that also holds back ice, not only snow.
It is still another object of the present invention to provide an on-the-roof ice and snow holding apparatus that is not corrodible and U.V. proof.
It is another object of the present invention to provide and on-the-roof ice and snow holding apparatus that is aesthetically pleasing and which can be made to match various roof colors when required.
A snow guard for a raised portion on a building surface, having a unitary transparent mounting body is formed from a polycarbonate material. A transparent acrylic snow-holding bar fits into the transparent mounting body. An ice-holding bar also is provided and is formed from clear acrylic. In one aspect, the mounting body includes vertical structural stiffeners 30 by walls 42 of bar supporting central columns 32 and by outside surface 38 of wall 24 and horizontal stiffeners 27 extending downwardly under top 26 and which are integral part of the mounting body and of walls 24 providing a rigid, strong connection of the two structural support sides 28, top portion 26 and horizontal stiffeners 27 and structural support sides 28 all molded in one piece, made of ultraviolet proof, high impact, high izod polycarbonate plastic. In one aspect, the mounting body include bar insertion cavities 46 and stops 52 to prevent snow-holding bar 8 from sliding through its insertion cavities.